This invention relates to an apparatus for controlling an internal combustion engine, and more particularly to a control apparatus capable of detecting and correcting both the dispersion of the torques and the dispersion of the air/fuel ratios, with respect to the respective cylinders.
With the growing concern about the global environmental problem, the requirement has been more and more increasing for reduction of the exhaust gas emission, namely the emission of CO2 or the fuel consumption, from an automobile. In order to improve the performance of operation, there have recently come to be disseminated the engines that employ variable control valves for the purpose of controlling not only the amount of fuel but also the amount of intake air, fed into the respective cylinders of the engine. For the same purpose, the pressure of injected fuel tends to be increased with the result that there is an increasing tendency that the amounts of fuel injection into the respective cylinders become uneven. With this type of engine, it is necessary to long secure, in the surroundings where the engine is used, the capability to control both the fuel injection amount and the intake air amount, that is, both the torques and the air/fuel ratios, for the respective cylinders of the engine.
JP-A-2004-52620 discloses an invention according to which the dispersion of the intake air amounts for the respective cylinders is detected/corrected by the air-flow sensor and then the dispersion of the air/fuel (A/F) ratios (i.e. fuel injection amounts) for the respective cylinders is detected/corrected by the air/fuel ratio sensor.